Studies in mice deficient in p38γ, p38δ, or both nonetheless show that these kinases have a pro-tumourigenic role and are needed for tumour development; p38δ deficiency reduced tumour formation in the chemical DMBA/TPA (7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol-13-acetate)-dependent model of skin carcinogenesis and in K-Ras-driven lung carcinogenesis [24]. Here, KRAS is linked to neoplasm.